Summer Vegetable Soup with Pesto

FOR SOUP: Place oil in a frying-pan over moderate heat, add onions and cook, stirring, until tender. Add tomatoes and cook, stirring, for 8 minutes. Bring stock to a boil in a large saucepan. Add carrots, potatoes, leeks, celery and onion and tomato mixture. Simmer for 15 minutes. Add green beans, zucchini, spaghetti and cooked beans. Simmer until vegetables are tender.

FOR PESTO: Place garlic, basil, cheese, oil and 1/4 cup of the hot soup liquid in a food processor and blend until smooth. Serve soup topped with a dollop of pesto.